Electric switch



(No Model.)

E. THOMSON.

ELECTRIC SWITCH.

No. 363,183. Patented May 17, 1887.

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UNITED STATES PATENT FHCEO ELIHU THOMSON, OF LYNN, MASSACHUSETTS.

ELECTRIC SWITCH.

SPECIFICATION forming part of Letters Patent No. 363,183, dated May 17,1887.

(No model.)

To all whom it may concern:

Be it known that I, ELIHU THoMsoN, a citizen of the United States, and aresident of Lynn, in the county of Essex and State of Massachusetts,have invcntedcertain new and useful Electric Switches, of which thefollowing is a specification.

My present invention relates to the construction of electric switchesdesigned to open or close or otherwise change the connections of anelectric circuit, and is designed more particularly to improve theconstruction and operation of switches adapted for use with incandescentelectric lamps.

The object of my invention is to attain simplicity of constructiomwhileat the same time securing the benefits arising from the opening of theswitch-contacts with aquick or sudden motion or snap, so as to preventburning of the same and rendering it impossible to leave the switch in ahalf closed or halfopen condition.

The object, further, is to so construct the switch that it shall be heldin closed condition by a positive means, requiring the eXertion of apositive force in order to open the switch.

My invention consists in the novel combinations and features ofimprovement more specifically designated in the claims at the end ofthis specification.

Inthe accompanying drawings, Figure 1 is a perspective view of a switchembodying my invention. Fig. 2 is avertical central section taken atright angles to the line of view of Fig. 1. Figs. 3 and 4 illustrate theelectrodes of the switch in closed and in partially-open position. Fig.5 is a plan of the devices employed for communicating a movement fromthe thumb-piece or handle of the switch to the movable electrode. Fig. 6is a diagram illustrating the connections of the switch to anincandescent electric lamp. Fig. 7 shows the parts of the switch whenthe same is fully open. Figs. 8 and 9 show the parts of a modi tied formof the switch in open and closed position, respectively.

B indicates a block of insulating or other material of any desired form,which constitutes a support, on which the various parts of the deviceare mounted. Secured to one side or end of said block is an electriccontactspring, S, forming one electrode of the switch, and whose freeend projects over the side of said block, or is located over an openingor depression in the same in proper position to engage with a rotary orswinging'contact plate, arm,orpiece, G,which forms the other electrode,and is adapted to be brought into and out of contact with the spring byturning or swinging, so that its contact portion shall move at angle tothe line of pressure of the spring when the same is under tension. Attheir engaging portions the two electrodes are adapted to interlock witha considerable degree of firmness by being formed one with a slightdepression and the other with a corresponding projection adapted toenter the depression when the switch is closed. This construction isconveniently attained by forming a depression or notch in the swingingplate or cam and bending the spring so as to form a projection that canenter the notch and be held in engagement with the same by theelasticity of the spring.

Motion may be given to the electrode 0 by means of a spindle or rodwhich is provided with an actuating-handle or thumb-piece, H, ofinsulating material, and turns in a bearing or seat formed of a tube orsleeve, T, of any suit-able conducting material, such as brass, and setin a bore or opening extending through the block transversely, as shown.

The operating thumb-piece H and the camplate or electrode that is turnedby the action of the thumb-piece are so connected with one anotherthrough the pin or spindle just mentioned that the plate is capable ofaslight free or lost rotary motion with relation to the thumbpiece. Amechanical connection that.

will permit of a slight independent motion of the character, while atthe same time giving the capacity of turning the plate or electrode 0 tothe extent necessary for producing the desired movement,is readilyobtained in various ways. A simple way of securing this end consists inmaking the spindle or stem that turns in sleeve T in two parts, one ofwhich consists of the metal pin G, carrying the handle H at one end andbored out or hollow at its opposite end to receive the other part,consisting of pin or stud X, carrying the cam or electrode 0. Connectionbetween the two parts is made by means of a pin, a, that is secured ICOto the part X and projects through a slot in the hollow portion of thepart G. The width of the slot at the point where the pin engages withits sides is made somewhat greater than the diameter of the pin, so togive the lost motion required.

The slot is preferably made short in the direction of the axis of thespindle, and the pin a is set into the stud X after the latter isinserted. After the shaft or spindle thus constructed has been placed inthe tube T the handle H may be attached, and the spindle or shaft isthen prevented from slipping out in either direction by the handle H andcam orplate- 0. If desired, the attachment of the plate 0 to the studyXmight be'reserved until afterthe compound shaft or spindle,with handle Hpreviously attached, is slipped into place. It may, however, be founddesirable to east the plate 0 and pin X in one piece, in which case theformer procedure would be adopted.

The parts described are made of some conducting material like brass, andelectrical connection to the electrode C from the conductor b is madethrough a clamp-screw and washer,setting against the side of the sleeveT in a cavity in the block,or through other suitable means of connectionwith said sleeve, and from; thence through the said sleeveand'eonducting-shaft, composed of parts G X, to the plate or electrode0.

Electrical connection between spring or electrode S and a conductor, d,forming the other pole of the circuit, and leading, for instance, fromone terminal of an incandescent lamp, is made in any desired manner-as,for instance, by clamping the end of the conductor to the fixed end ofthe spring S.

Applied to the swinging or turning electrode (1 is a spring, Z,connected at one end to the electrode 0 and at the other to the block13,0r other suitable support. This spring is so applied that it willpush or pull, as the case may be, nearlyin the line of the centeraboutwhich the electrode turns and the point at which said electrode andits opposite electrode S engage"sthat is to say, the spring pulls nearlyon a dead-center when the parts are in the poretain this position.

gaged and in the position shown in Fig. 3, where the two electrodes areinterlocked by reason of the spring action of S and the conformation ofthe contact parts: If the handle H be turned in either direction, theplate or arm 0 will be forcibly disengaged from the spring by the manualpower applied to the handle. The moment,however, that the plate isturned so far that it can escape the detaining action of 'the springSthe spring Z, whosepoint of attachmenthas been atthe sametime moved offthe dead-center, will act upon the electrode 0 and will (owing to thelimited independent movement permitted to the latter with respect to thehandle H) quickly and suddenlymove the same out of contact with oppositeelectrode S, despite the fact that the handle H may be held or may beallowed to move only with such tardiness that, without such capacity forindependent movement, the contact parts of the electrodes would beinjuriously burned.

By the means described arcing and burning due to slow rupture of contactat the electrode or false contact are effectually avoided, and theobjections that would be incident'to a rigid connection of the-handleand the electrode G are effectually prevented. If such rigid connectionexisted, it is evident that the velocity of motion of the electrode atthe time of breaking contact would be limited to the velocity of motionpermitted to the handle H by the hand of the operator, and a burning ofthe contacts would ensue. When, however, the part G is turned, the forcerequired to disengage the locked electrodes brings the pin into contactwith one side of the slot; but as soon as the electrode is disengagedand can move freely the spring Z moves it quickly, until the pin a isbrought to the other side of the slot in G, the movement of the pin inthe slot thus produced being the gage of the limited free or independentmovement permitted to the electrode with respect to its operatingthumb-piece or handle.

In Fig. 4 the parts of the switch are shown at an intermediate stage ofmovement after disengagement of the electrodes has been effected.

Fig. 7 shows the position which the parts assume after the handle H isreleased from the finger of the operator. The handle H may be used in anobvious manner to restore the parts to the position shown in Fig; 3,when it is de sired to complete the circuit.

Without changing the manner of action of the switch, it may be made tomake contact and open contact twice in a revolution of the handle H bythe modification shown in Figs. 8 and 9. r f

The plate Ois made with its two ends alike, with notches for thereception of the spring S, and the spring Z is made with a small opentriangle or other shape, permitting the inelosure of two pins orprojections on the plate G, and so formed that the tendency of thespring Z will be to throw it into the position shown in Fig. 8 whenrelieved from theretaining action of the spring S; (the positionindicated in Fig. 9.) In this case the switch will be open when thepiece 0 is in the position shown in, Fig. 8, and will be held in thatposition by the action of the spring Z, holding one side of the IIOtriangular piece against two pins, as shown.

What I claim as my invention is 1. The combination, in an electricswitch or turn-oft, of two electrodes having one a depression and theother a corresponding projection by which they may be normally locked byspring action, and an operating knob or handle connected with oneelectrode through devices permitting a limited free movement of theelectrode with relation to the operating knob or handle.

2. The combination, in an electric switch or turnoff, of electrodes, onehaving a depression and the other a projection normally interlocked byspringpressure, an operating knob or handle for unlocking the partsagainst the action of the spring-pressure, a connecting mechanismbetween a movable electrode and the operating knob or handle, permittinga limited free movement of the electrode, and a spring applied to saidelectrode, as and for the purpose described.

3. The combination, in an electric switch or turn-off, of aspring-electrode, a turning or swinging plate electrode, a projection onone electrode adapted to rest normally in a depression upon the other,and an actuatingspring for the turning electrode normallypulling on adead-center and connected wit-h the same, so as to be moved off thecenter when the electrode is turned to disconnect it from the oppositeelectrode.

4. The combination, in an electric switch or turn-off, of a springconnected to the contactclosing arm and normally acting on the same on adead-center, said spring being connected to the circuit-closing arm, asdescribed, so that it is moved off the dead-center when the switch isoperated to break the circuit.

5. The combination, in an electric switch, of two electrodes whosecontact surfaces are formed one with a depression and the other with aninterlocking projection, and an operaling knob or handle connected withthe movable electrode through mechanism having a lost motion, as and forthe purpose described.

6. The combination, in an electric switch, of a swinging plate or blockconnected with a spindle and forming one electrode, a spring forming theother electrode,a depression in the contact-surface of one and aprojection in the contact-surface of the other adapted to interlock, anda spring connected with said swinging plate or block and pulling, whenthe electrodes are engaged, 011 a substantially deadcenter.

7. The combination, in an electric switch, of

a swinging or turning electrode normally held from disconnection withits opposite electrode by spring-pressure, an operating-spindle andthumb-piece, mechanism between the thumbpiece and the electrode operatedthereby, whereby said electrode may have a limited free movement, and aspring exerting its force upon the swinging electrode normally on adead-center, as and for the purpose described.

8. The combination, with a contact plate or cam, 0, moving in the arc ofa circle, of an elastic spring, S, engaging with and closing circuitupon the same and tending to hold said plate from disconnecting orbreaking circuit, and a spring, Z, for throwing said cam from contactposition when said spring is moved from its dead-point.

9. The combination, with the spring S, bent as described, and thenotched plate or cam turning with a spindle or axis, of a handle, H,connected to the cam through parts having a lost motion, asdescribed,and a eircuitbpening spring connected to the plate or cam.

Signed at Lynn in the county of Essex and State of Massacln1setts,this24th day of N ovcmher, A. D. 1885.

ELIHU THOMSON.

Witnesses:

M. L. THOMSON, XVILLIAM F. NooNAN.

